Q63 — AWS SAA-C03 Ch.17

Question 63 of 89 | ← Chapter 17

Q1363. A company is building a solution to provide customers with an API that accesses financial data. The API backend needs to compute tax data for each request. The company anticipates greater demand to access the data during the last 3 months of each year. A solutions architect needs to design a scalable solution that can meet the regular demand and the peak demand at the end of each year.Which solution will meet these requirements?

• A. Host the API on an Amazon EC2 instance that runs third-party software. Configure the EC2 instance to perform tax computations.
• B. Deploy an Amazon API Gateway REST API. Create an AWS Lambda function to perform tax computations. Integrate the Lambda function with the REST API. ✓
• C. Create an Application Load Balancer(ALB) in front of two Amazon EC2 instances. Configure the EC2 instances to perform tax computations.
• D. Deploy an Amazon API Gateway REST API. Configure an Amazon EC2 instance to perform tax computations. Integrate the EC2 instance with the REST API.

Correct Answer: B. Deploy an Amazon API Gateway REST API. Create an AWS Lambda function to perform tax computations. Integrate the Lambda function with the REST API.

Explanation

The correct answer is B. Deploy an Amazon API Gateway REST API. Create an AWS Lambda function to perform tax computations. Integrate the Lambda function with the REST API.Explanation:The company needs a scalable, cost-efficient, and low-maintenance solution that can handle:Regular demand (steady traffic).Peak demand (high traffic during the last 3 months of the year).Why Option B is the Best Choice:AWS Lambda for Tax ComputationsAutomatically scales with demand (no need to provision or manage servers). Pay-per-use pricing Cost-efficient for variable workloads (no over-provisioning). Stateless execution Ideal for API requests (each request is independent).Amazon API GatewayManages API traffic (throttling, authentication, caching).Integrates seamlessly with Lambda (no need for manual load balancing).Supports REST APIs (standard for financial data access).Handles Peak Demand EfficientlyLambda auto-scales during high traffic (e.g., end-of-year rush). No need to pre-warm instances (unlike EC2-based solutions).Why Other Options Are Incorrect:A. Host API on a single EC2 instanceSingle point of failure If the instance crashes, the API is unavailable. Manual scaling required Must provision extra capacity for peak demand (inefficient and costly). Operational overhead Must manage patches, backups, and monitoring.C. Use ALB with two EC2 instancesLimited scalability Only two instances may not handle peak demand (must manually scale). Higher cost Paying for idle capacity during low traffic periods. Still requires management EC2 instances need updates and monitoring.D. API Gateway + EC2 (instead of Lambda)EC2 does not auto-scale Must manually scale up/down (risk of downtime or over-provisioning). Higher operational overhead Managing servers instead of relying on serverless.Comparison Table:OptionScalabilityCost EfficiencyOperational OverheadBest For B(Auto-scaling Lambda)(Pay-per-use) (Minimal)Variable workloads (peak demand) A (Single instance) (Fixed cost)(High)Legacy apps (not recommended) C (Manual scaling) (Over-provisioning)(Moderate)Predictable, moderate traffic D (Manual EC2 scaling) (Fixed cost)(High)Apps needing EC2 (not tax APIs) Conclusion:Option B is the most scalable, cost-effective, and low-maintenance solution because:Lambda auto-scales Handles peak demand without manual intervention. API Gateway manages traffic No need for load balancers or custom scaling logic.No server management Reduces operational complexity.Avoid Options A, C, and D (they introduce scaling challenges or unnecessary management tasks).Final Answer: B